Primer pump

ABSTRACT

FUEL PRIMER APPARATUS FOR USE IN CONNECTION WITH INTERNAL COMBUSTION ENGINES FOR VEHICLES SUCH AS SNOWMOBILES AND THE LIKE. THE APPARATUS IS CHARACTERIZED BY ITS RELATIVELY LIGHT WEIGHT AND COMPACT CONSTRUCTION, AND IT IS ESPECIALLY SUITABLE FOR MOUNTING ON A SNOWMOBILE COWLING FORMED OF A THIN SHEET OF PLASTIC MATERIAL. IT COMPRISES A UNITARY STRUCTURE OF A PRIMER BULB AND A CHECK VALVE ASSEMBLY WHICH IS CONSTRUCTED AND ARRANGED SO THAT A PRESSURE DROP TO ITS DISCHARGE END INDUCED BY OPERATING CONDITIONS WILL BE INSUFFICIENT TO INDUCE UNDESIRED FLOW OF FUEL THROUGH THE APPARATUS TO FLOOD THE ENGINE.

PRIMER PUMP INVENTORS wmus E. TUPPER JOHN R. HANSON OLSEN & STEPHENSON ATTORNEYS July 11, 1972 w TUPPER ETAL Filed Jan. 7, 1971 mmqu lzwc. mm w\ 1 km @N N whbm 6 United States Patent Oifice 3,676,026 Patented July 11, 1972 3,676,026 PRIMER PUMP Willis E. Tupper and John R. Hanson, Dexter, Mich.,

assignors to Dexter Automatic Products, (30., Inc.,

Dexter, Mich.

Filed Jan. 7, 1971, Ser. No. 104,654 Int. Cl. F04b 21/02, 39/10; F16k 15/00 US. Cl. 417-560 5 Claims ABSTRACT OF THE DISCLOSURE Fuel primer apparatus for use in connection with internal combustion engines for vehicles such as snowmobiles and the like. The apparatus is characterized by its relatively light Weight and compact construction, and it is especially suitable for mounting on a snowmobile cowling formed of a thin sheet of plastic material. It comprises a unitary structure of a primer bulb and a check valve assembly which is constructed and arranged so that a pressure drop at its discharge end induced by operating conditions will be insuflicient to induce undesired flow of fuel through the apparatus to flood the engine.

CROSS-REFERENCE TO RELATED APPLICATION This application is a modification of the invention disclosed and claimed in pending application Ser. No. 34,691, filed May 5, 1970 in the name of Willis E. Tupper et al. for Primer Pump.

BACKGROUND OF THE INVENTION The present invention relates to an improved fuel primer pump assembly adapted particularly, but not exclusively, for use with the fuel system of a snowmobile.

It is conventional practice to provide snowmobiles with small two-cycle gasoline engines for propulsion purposes, and it is normal practice to include in the fuel system a manually operable fuel primer pump to provide enriched fuel mixtures for starting purposes and the like. One of the problems that arises in connection with the prior fuel systems is that when the engine is decelerated rapidly, it frequently is flooded, and therefore, stalls. This results from an undesired flow of fuel from the primer pump induced by the partial vacuum created at the carburetor when the engine is suddenly decelerated. It is known to provide check valves in the fuel system to overcome this problem, but such check valves are normally located separately from the primer pump and necessitate the use of relatively complex arrangements of fuel feed lines and valve means which are either unsatisfactory in use or are unnecessarily expensive.

A primer pump which has overcome the shortcomings of the prior art is disclosed in the aforesaid prior application, Serial No. 34,691. The primer pump shown in the prior application has proved to be very satisfactory in use, but it is designed essentially for mounting on a rigid structural supporting surface of the snowmobile. In some instances it is desired that the primer pump be mounted on relatively thin plastic cowlings, and the like, which cannot support relatively heavy items and in such instances a relatively lightweight primer pump must be provided to avoid damage to the mounting surface for the primer pump which otherwise might occur because of the rough driving conditions to which snowmobiles are frequently exposed.

SUMMARY OF THE INVENTION The present invention has overcome the shortcomings of the prior art, and has provided an improved fuel primer pump which includes in a single unitary lightweight construction, check valve elements which cooperate with a primer bulb to provide necessa fuel priming and at the same time to prevent undesirable flooding of the engine.

According to one form of the present invention, a pump assembly is provided comprising a housing which defines an internal chamber, one end of which has inlet and outlet passages in communication with the interior of the chamber. The remainder of the housing is defined by a resilient bulb. A resilient unitary umbrella valve element is supported in the outlet passageway and has a portion overlying the inlet passageway to permit inward flow only of fluid into the chamber and has an outlet port throughv which fluid can flow from the chamber to the outlet passageway. A check valve element is mounted downstream of the outlet port in the one end of the housing so as normally to close the outlet port, and the check valve element is responsive to a preselected pressure condition caused by the application of pressure to the bulb to open so as to discharge the fluid in the chamber to said outlet passageway. The umbrella portion is responsive to a pressure drop in the chamber caused by the return of the bulb to its distended position to open so that fluid can flow from the inlet passageway into the chamber.

In the preferred form of the invention the check valve element in the outlet passageway is a spring loaded ball mounted to close the outlet side of the port in the umbrella valve element. The stem portion of the umbrella element is snap-fitted into an annular groove in the outlet passageway.

The one end of the housing containing the passageways is a fitting which can be connected to a thin apertured panel for supporting the primer pump, and the fitting is adapted to be disconnected so that the resilient bulb can readily be removed from the one end to make the valve elements in the housing accessible for cleaning or repair purposes.

The present invention is described in connection with its use as a fuel primer pump, but it will be recognized by those skilled in the art that this pump assembly can be used equally well in other applications where a small lightweight pump may be required.

Thus, it is an object of the present invention to provide an improved primer pump assembly for use with internal combustion engines, but which is also suitable for other applications wherein manual pumping of small quantities of fluid is desired.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 illustrates partially in longitudinal section a primer pump embodying the present invention, and illustrates schematically a portion of the fuel system with which the primer pump is adapted for use;

FIG. 2 is a fragmentary view showing the action of the pump when fluid is being drawn into the pump chamher; and

FIG. 3 is a view similar to FIG. 2, but illustrating the action of the pump when the resilient bulb is compressed to force fluid out of the outlet passageway.

DESCRIPTION OF THE PREFERRED EMBODIMENT Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawing, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed 3 herein is for the purpose of description and not of limitation.

Referring now to the drawing, the invention will be described in greater detail. As there shown, the fuel primer pump is mounted in a relatively thin plastic panel 12 and is connected as part of a fuel system 14. The latter includes a gasoline tank 16, a carburetor 18, a main fuel line 20 extending from the gasoline tank 16 to the carburetor 18, a supply line 22 in communication with the gasoline tank 16 via the line 20 and connected at the other end to the fuel inlet fitting 24 of the primer pump 10. A fuel outlet fitting 26 is connected to the fuel line 28 which communicates with the carburetor 18 in the conventional manner to permit introduction of the desired mixture of fuel to the associated internal combustion engine (not shown).

The pump primer 10 has a pump housing 30 which includes the resilient primer bulb 32 and the header or one end portion or fitting 34. The header or one end portion 34 closes the open end of the primer bulb 32 and includes a peripherally located inlet passageway 36 and a central outlet passageway 38, both of which are in communication with the internal chamber 40 defined by the housing 30.

The one end 34 of the housing 30 is externally threaded at 42 for threadedly receiving the lock nut 44 and for threadedly receiving the cup-shaped element 46. The latter is adapted to fit around the outer periphery of the primer bulb 32 so as to lock the inturned lip 48 thereof into the annular groove 50 of the fitting or one end 34. As can be seen, the cup-shaped member 46 can be screwed into the position illustrated in FIG. 1 for securing the primer bulb in its sealed position after which the fitting can be introduced through a hole in the panel 12 and the lock nut 44 can be screwed into place to lock the primer pump 10 in the mounted position. If it is desired to gain access to the interior of the housing for repair or maintenance purposes, such access can readily be obtained merely by removing lock nut 44 and loosening the cupshaped member 46 so that the primer bulb can be removed from its seated position on the fitting 34.

The inner end of the outlet passageway 38 formed in the end member 34 defines an inwardly facing annular seat 52, and a resilient unitary umbrella valve element 54 is seated on the inner face of the annular seat. The umbrella valve element 54 has an umbrella portion 56 overlying the inlet passageway 36 permitting inward flow only of fluid into the chamber 40. The umbrella valve element 54 has a central outlet port 58 through which fluid can flow from the chamber 40 to the outlet passageway 38. The stem portion 60 of the umbrella valve element defines the central outlet port 54 and also includes an annular groove 62 in which the shoulder portion 64 extends to secure the umbrella valve element in place. It will be recognized that the umbrella valve element 54 can readily be inserted in place merely by a snap action produced by pressing the stem into the inner end of the passageway 38.

Located on the downstream side of the umbrella valve element 54 is a ball check valve assembly 66 which comprises the ball element 68 and the compression spring 70. The ball check valve assembly 66 is mounted so that the ball will be seated against the outlet end of the port 58, and the spring 70 is calibrated so that it will provide sulficient biasing action of the ball 68 against the seat provided at the outlet end of port 58 so as to prevent opening if a pressure drop occurs in the fuel line 28 as a result of a partial vacuum being created in the carburetor 18.

By virtue of the described arrangement, when the primer bulb is manually compressed, the liquid fuel in the chamber 40 will be urged through the port 58 forcing the ball element 68 ofi the seat so that a measured quantity of fuel will be introduced into the carburetor. When the primer bulb 32 is released, its resilient properties will return it to its normal position thereby creating a pressure drop within the chamber 40 which will induce the flow of fuel from the gas tank 16 through the inlet passageway 36 to again re-charge the chamber 40 with fuel for use in subsequent priming operations.

It will be recognized that during the re-charging step, the check -valve 66 will be closed, and the umbrella portion 56 of the umbrella valve will open to a position such as is shown in FIG. 2. When the fuel is discharged from the primer pump, the umbrella portion will be in a closed position and the check valve 66 will be in the open position such as is shown in FIG. 3.

From the foregoing description it will be understood that undesirable flooding of the engine which would cause stalling is prevented, and this is accomplished by a relatively lightweight primer pump which is constructed and arranged to assure trouble-free operation.

It is claimed:

1. A pump assembly comprising a housing which defines an internal chamber, one end of said housing having inlet and outlet passageways in communication with said chamber, the remainder of said housing being a resilient bulb, said outlet passageway having an inwardly directed shoulder adjacent to said chamber, a resilient unitary umbrella valve element supported in said outlet passageway having an umbrella portion overlying said inlet passageway permitting inward flow only of fluid into said chamber and having a flexible stem portion which defines a central outlet port through which fluid can flow from said chamber to said outlet passageway, said stem portion having an annular groove into which said shoulder extends to secure said valve element in place, a check element mounted downstream of said outlet port in said one end of the housing normally closing said outlet port and responsive to a selected pressure caused by collapsing of said bulb to open so as to discharge the fluid in said chamber to said outlet passageway, said umbrella portion being responsive to a pressure drop caused by said resilient bulb returning to its distended position to open so that fluid can flow from said inlet passageway into said chamber.

2. The pump assembly that is defined in claim 1, wherein said check element is a spring-loaded ball check assembly mounted in said one end so that the ball is normally seated against said port to close the same.

3. The pump assembly that is defined in claim 1, wherein said one end has an external threaded portion and a lock nut is threadedly connected to said threaded portion for retaining the pump assembly on a panel containing an aperture through which the resilient bulb can project.

4. A combination primer bulb and check valve assembly for an internal combustion engine comprising a fitting adapted to be mounted in an apertured panel, said fitting having an axial extending outlet passageway and an inlet passageway spaced therefrom, a resilient unitary umbrella valve element having a hollow flexible stern portion supported in said outlet passageway and an umbrella portion overlying said inlet passageway, said outlet passageway having an inwardly directed shoulder, said stem portion having an annular groove into which said shoulder extends to secure said resilient unitary umbrella valve element in place, a resilient bulb releasably secured in sealed relation to the outer periphery of said fitting to define with the fitting an internal chamber, a ball check valve element spring-urged against the downstream side of said hollow stem so that communication between the outlet passageway and said internal chamber is normally closed, said resilient bulb being collapsible for discharging fuel in said chamber past said ball check valve element and through said outlet passageway and being distensible thereafter to draw fuel through said inlet passageway and past said umbrella portion.

5. A pump assembly comprising a housing which de fines an internal chamber, one end of said housing having inlet and outlet passageways in communication with said chamber and an externally threaded portion, the remainder of said housing being a resilient bulb, a resilient unitary umbrella valve element supported in said outlet passageway having an umbrella portion overlying said inlet passageway permitting inward flow only of fiuid into said chamber and having a central outlet port through which fluid can flow from said chamber to said outlet passageway, a check element mounted downstream of said outlet port in said one end of the housing normally closing said outlet port and responsive to a selected pressure caused by collapsing of said bulb to open so as to discharge the fluid in said chamber to said outlet passageway, said umbrella portion being responsive to a pressure drop caused by said resilient bulb returning to its distended position to open so that fluid can flow from said inlet passageway into said chamber, a lock nut threadedly connected to said threaded portion for retaining the pump assembly on a panel containing an aperture through which the resilient bulb can project, said resilient bulb having an inturned lip and said one end having a groove in which said inturned lip is seated, and an annular cup-shaped ele- UNITED STATES PATENTS 2,537,241 1/1951 Smith 417-560 3,153,381 10/1964 Holley, Jr. 137-512.4 X 3,434,808 3/1969 Pobst, Jr 417-567 X 2,690,278 9/1954. Bacheller 417-567 X 2,662,723 12/1953 Coffey 417-566 X ROBERT M. WALKER, Primary Examiner US. Cl. X.R. 

